Why Falklands coastal batteries prepared for torpedo boats

Why did Falklands coastal defences expect torpedo boats?

They feared improvised torpedo craft assembled from regional German personnel and motorboats, not necessarily a formal enemy flotilla.

The Second World War concern did not require a formal German torpedo-boat flotilla to cross the South Atlantic. British planners feared that German communities and shipping in South America might clandestinely obtain motorboats and the equipment needed to arm them. The adapted craft could then raid the Falklands in small numbers. Coastal guns therefore answered an improvised regional threat rather than a prediction of a conventional enemy squadron.